Trapdoor newbie w/ one picture - of buttplate markings

Came across a Springfield Trapdoor rifle (not a carbine) today. Not knowing what were the important features to note, I took only one photo. I couldn't see a year of manufacture, but likely wasn't looking in the correct spots. I can tell you, it appears complete, had double upper stacking/sling swivels and now that I've had a bit of time with the Google, that it has a ramrod bayonet. Beyond that I can bring no more information to discussion. The photo I took was of the markings stamped into the butt tang - attached here.

69
C
61

So, I am curious about what the regimental markings represent, and pointers on what else to look for when I get another chance to take a look at it, especially those things which would help narrow down a value range. I would put the condition at somewhere between at good - can't speak to the bore. I'll take a light with me next visit.

I watched a few listings on GunBroker before I found my trapdoor. From what I saw, I’d say any trapdoor with full wood stock and decent bore is going to bring around $700 or so.
Rare variations notwithstanding, of course.
Then I know from experience that even a reallllly bad shape trapdoor is worth an easy $400 in parts alone.
Now I’m no expert so I’m afraid I won’t be much help other than those prices...but I hope it helps in your decision a little.

There are collectors that can decipher most of the US markings, just have to find them!

This butt plate tang on a early Model 1903 stock is as follows: Troop H 8th Cavalry Trooper 18
as I was told by a collectorAttachment 94422Attachment 94423

Attachment 94424There are collectors that can decipher most of the US markings, just have to find them!

This butt plate tang on a early Model 1903 stock is as follows: Troop H 8th Cavalry Trooper 18
as I was told by a collectorAttachment 94422Attachment 94423

Could well be sixty ninth New York, company C , rifle in rack number sixty one.

Thanks all. I'm going to try to get back for another, better, look at the Trapdoor.